1. Cross-Reference to Related Application
This application claims the benefit of U.S. Provisional Application No. 60/013,370, filed on Mar. 15, 1996.
2. Field of the Invention
The invention relates to a method and apparatus for creating and broadcasting predefined signals designed to selectively modulate the behaviors of species of fish, marine mammals, crustaceans, etc.
3. Background Art
It has long been known that acoustical signals are both generated and detected by aquatic animals and are an important communications medium. Furthermore, certain species of aquatic animals appear to transmit an acoustical signal unique to the species and equivalent to a "signature." The signature can be detected and may be recognized as indicative of available prey or indicative of the presence of a predator. Sound corresponding to such a signature may be reproduced and broadcast underwater and the behavior of fish and other aquatic animals may be influenced or controlled. Many aquatic animals produce "calls" indicative of social behavior or distress, or the like, and the corresponding underwater sounds influence the behavior of both predator and prey. The behavior of aquatic animals is also known to be influenced by weather disturbances which create sound transmitted from the surface of the water.
As described in my prior patent, U.S. Pat. No. 5,177,891, issued Jan. 12, 1993, and entitled "Game Fish Attracting Device," methods for recording underwater acoustical signals are known. Recording acoustical signals produced by particular species of aquatic animals involves isolating members of that species and detecting signals by means of an underwater acoustical transducer. However, isolating different species in an area where underwater sounds can be recorded is often difficult and at least inconvenient. Furthermore, in such a setting it is likely that the species of aquatic animals will only generate certain types of signals and not, for example, the kind of signals that would be generated in the presence of a predator or the kind of signals that would be produced by a predator in pursuit of prey, or those that might be associated with certain social behaviors.
The concept of influencing or controlling the behavior of aquatic animals, which term is understood to include fish, marine mammals, crustaceans, and any other animals who make water their habitat, has wide application. Such control or manipulation may be used in many applications, including sport fishing, commercial fishing, scuba diving, marine research, selective commercial netting, etc. An example of the latter application would be repulsion of dolphins from commercial tuna nets. The same principles may be applied in repelling sharks or other predators.
One prior art approach to attracting fish to a particular location is to retain a number of fish in a tank, or the like, and to record their sounds for rebroadcast at a later time. One problem with that approach is that the sound that is being recorded may include ambient noise or may be distorted by echoes, or the like, occurring in the tank, which do generally not occur in the natural habitat. As a result, the broadcast sounds do not correspond directly to the sounds that would normally be produced by a particular species of aquatic animals in a natural habitat.